1. Selecting the trap did not automatically import the OID's. Had to manually enter them.
2. When selecting by OID - make sure you get your order right. The move up / Move down does not work. I got the first one wrong - and therefore the following 12 as well. No way to fix.
3. If you know the order the OIDS will come in - much quicker just to select position and do them in order.
4. As the OID text is not carried across - don't waste your time entering it.
5. When formatting the Alarm in Event Processing Policy - watch out for 256 char limit. UCS traps, when including /n for new line, exceed 256 chars.
6. Copy and paste within  Event Processing Policy when you have used all 256 chars gives an error. Copy and paste from Notepad ++  instead.
7. Alarm log shows Event before Message however Alarm Browser does not - makes for a very busy and messy screen.
8. Alarm Detail is weird - it allows me to show my shortened version of Message in Related Events (without the event title) - in Overview - gives me the whole message only.
9. When hovering over the alarm in Alarm Browser - I get the line by line message - but again, I do not get the Event Message or the Event.
10. Nearly forgot - Creation Time and Modification time are Octet Strings - no way to have NetXMS interpret them - come through as rubbish chars.

So there it is - I managed to get two traps in - with significant effort. Hopefully some of these will be improved.

Here is example of correctly formatted trap with times in corrected format.